Digital watermarking (hereinafter “watermarking”) allows electronic content creators to attach digital information (e.g., a pattern and/or text and/or cryptographic key containing, for example, copyright, authorship, ownership, usage information) to their electronic content to identify themselves as the creator of the content. This information can be recovered even if the watermarked content is altered or degraded. A watermark thus provides proof of ownership.
When decoded, a watermark can be used to determine if the electronic content has been copied, altered, and/or distributed without permission. Unlike encryption used to restrict access to data, watermarking provides evidence of authorship and usage. As with data hiding, generally, the watermark remains with the media through typical content-preserving manipulations, e.g. cropping, compression, and so forth. In contrast to data hiding, however, the watermark cannot be accessed by an unauthorized user.